Characteristics of vomiting associated with acute sustained release theophylline poisoning: implications for management with oral activated charcoal.

Vomiting in acute theophylline toxicity has assumed increased clinical importance since the introduction of multiple dose activated charcoal therapy. We performed a prospective study of 26 patients with acute overdose of sustained release theophylline to characterize vomiting, and its possible interference with the acceptance of activated charcoal. Twenty five of 26 patients vomited. The duration of vomiting correlated with both peak serum theophylline concentrations (p less than 0.001) and the duration of theophylline toxicity (p less than 0.001). Vomiting extended over 63% of the drug's absorptive phase (the time interval between ingestion and the peak level) and 49% of the elimination phase (the time interval between the peak level and decrease of theophylline level to less than 20 mcg/ml). Patients with peak serum theophylline concentrations less than 70 mcg/ml were able to accept larger amounts of activated charcoal than patients with serum theophylline concentrations greater than 70 mcg/ml (113 +/- 15 gms vs. 57 +/- 24 gms, p less than 0.05). Vomiting in acute sustained release theophylline toxicity is protracted, and limits the use of activated charcoal especially in patients with severe acute theophylline poisoning.